(1) Field of the Invention
The present invention relates generally to a guide to assist the operator of a vehicle in tracking the position of an attached, unloaded, boat trailer when the trailer is being backed in to the water, and in particular to a guide that will automatically assume an upright position when the trailer is out of the water, but which will be automatically lowered when the trailer is backed into the water, preventing damage to the guide when a boat is loaded onto the trailer.
(2) Description of the Prior Art
Numerous prior art devices have been proposed to assist the driver of a towing vehicle in ascertaining the position of an attached, empty boat trailer. For example, U.S. Pat. No. 5,596,944 to Massie describes a guide device comprised of a mounting bracket for attaching the device to a boat trailer, and an elongated signal rod or staff that is pivotally attached to the bracket. The signal rod has a weighted lower end, urging the rod to the vertical position. When the trailer is empty, the rod rotates to the vertical position. Contact of the rod with a boat loaded onto the trailer forces the rod to a horizontal position beneath the boat.
Another guide device, described in U.S. Pat. No. 4,940,251 to Willmsen, uses a water scoop at the lower end of the rod to scoop water when the boat is backed into the water. Thus, as with the Massie device, the rod is in an upright position when the trailer is empty, whether the trailer is in or out of the water, and is forced to a horizontal position when the trailer is loaded.
U.S. Pat. No. 4,958,436 to Tusche describes a trailer hitch guide comprised of a plurality of signal flags attached to the boat trailer with springs, so that the flags are normally in an upright position. When the trailer is loaded, the boat forces the flags to a horizontal position beneath the boat.
U.S. Pat. No. 3,863,594 to Gawthorp describes a similar structure, except that the flags are manually moved to the desired position. The flags are attached to the trailer in positions such that the flags do not contact or otherwise interfere with loading or unloading the boat.
One of the major difficulties with these prior art devices, with the exception of the Gawthorp device, is the fact that they rub against the boat hull during loading and unloading, potentially damaging or even breaking the device. Gawthorp recognizes this problem, but requires manual movement of the device between raised and lowered positions, which can be inconvenient when the driver is alone, especially if the boat trailer is in the water.
Thus, there is a continuing need for a boat trailer guide device that will assist the driver of a towed vehicle in determining the position of an empty boat trailer, especially when the trailer is being backed into the water. There is especially a need for a device that will automatically assume a raised, visual position when the unloaded trailer is out of the water, and a lowered, protected position when the trailer is in the water.